The present invention relates to an improved feeder apparatus for automatically controlling the tension of a yarn, including an electronic device for detecting possible faults, which can be applied to machines for making fabrics, knitted fabrics and cloth articles, and to textile machines in general.
As is known, in knitting machines and other textile machines there are usually provided several yarn feeders which conventionally comprise two small levers, articulated at different articulation points, which cooperate with corresponding switches.
These switches are independent from one another and and are adapted to disenergize the machine as a yarn is broken, by signalling a possible breakage of the yarn by means of individual light displays.
Also known is that conventional circular knitting machines are supplied with a lot of yarns, the tension of which must be controlled immediately upstream of the yarn inlet to the machine for a proper operation of the latter.
This control is at present performed manually, yarn by yarn, by using mechanical or electronic tension measuring devices, which must be held in a hand of the operator, whereas the operator by his other hand, adjusts the knitted fabric.
Moreover, in prior knitting machines, the operator controlling possible faults of the yarn feeders, must walk about the machine, which may have a diameter up to 2.5 metres, in order to detect the yarn feeder the yarn of which is broken.
This, as it should be apparent, requires a lot of time with a consequent decrease of the textile machine yield.
Moreover, the delays in recovering the proper operation of the machine are further increased by the fact that the individual displays, provided for displaying the yarn breakages, are frequently scarcely visible because of powder and the like, and because of the high lighting usually provided in the textile machine room.
Thus, the operation the textile machine is frequently stopped, with a consequent loss of time by the operator, even if the machine ne is not in a fault condition.
This drawback occurs because possible small impacts, or increases of the tension of the yarns, of very short duration, due, for example, to a badly wound bobbin or between the end of a bobbin and the start of a subsequent bobbin, or, moreover because of dirt accumulating between the yarn braking discs.
Accordingly, the above mentioned temporary variations of the tension of the yarns, cause the related movable mechanical lever to vibrate and the textile machine to stop since the lever undesirably impacts against the corresponding switch.